Thermal insulation expresses the capacity of a material or structure to prevent heat from being transferred from one location in space to another (other definitions exist). Thermal is an adjective.

The equivalent for sound is simply sound insulation, though I didn't find sound (as a vibration of the air) as being defined (in a dictionary) as an adjective, but it is here, isn't it?

What is the equivalent of thermal insulation for odor? Simply odor insulation, or maybe smell insulation? As for sound, I didn't find odor defined as an adjective. So should one maybe say odoriferous insulation? odoriferous is an adjective but it usually refers to something with a bad smell which isn't particularly what I want to express: odor transferred can be neutral, pleasant or not.

Usage examples:

  • Thermal insulation of this hotel room is good.
  • Sound insulation of this house is poor.
  • Odor insulation of that room is surprisingly poor (?)
  • 2
    Do you mean filtration — for odors? Jul 21 at 5:27
  • 2
    Odors are carried via air, so if you're smelling something that you shouldn't be smelling, it means that the ventilation is not good Jul 21 at 5:44
  • 4
    @JulianaKarasawaSouza Lack of ventilation is a cause, not a description of how the odour came to be there in the first place. How did it get there in the first place, before it's cleared by ventilation? I believe calocedrus is wanting a term [if there is one] akin to "odour-proof". Odour-proofness is clumsy to the point of comic; "odour insulation" is a similar structure to "sound insulation" where odour is an attributive noun (functioning as an adjective). Is there a better way of putting this concept?
    – Andrew Leach
    Jul 21 at 6:57
  • 2
    Does some form of hermetic work?
    – Cascabel
    Jul 21 at 13:48
  • 2
    There is an inaptness to the physical analogy, so you won't get a perfect answer without describing how the odor is prevented from migrating. (Look at laboratory exhaust hoods and read about "capture velocity" if you think barriers or filtration are the only ways.) Heat can be transferred by conduction (which thermal insulation is intended to inhibit) in which only energy moves, as well as other mechanisms like convection, which rely on the movement of matter.
    – Theodore
    Jul 21 at 16:23

odor proofing

Example (1959) These might be listed as follows ... 2.Odor proofing materials and articles made therefrom...

Example (1960) ...germ, mildew, mold, odor, and fungus proofing of textiles, paper, clothing, shoe linings, blankets, mattresses, and household and personal ...

(2018) Furthermore, if the lid became chipped, insect and odor proofing would be lost. Appropriate Technology in Vector Control

(1952 ) ...shipped in liners which are dirt-proof, dust-proof, odor-proof and must... Material Handling Engineering

  • Good one. I'd suggest odorproofness if looking for the noun version. A Google search turns up a number of references to this word being used.
    – thomj1332
    Jul 21 at 14:49
  • I think the gerund is used when a noun is needed, similar to soundproofing, waterproofing. sunbathing, fishing.
    – DjinTonic
    Jul 21 at 14:56
  • This is probably the best choice. It could even refer to methods that don't involve sealing.
    – Theodore
    Jul 21 at 16:28
  • @DjinTonic +1 this is good though already suggested (odor-proof) by AndrewLeach in an early comment above, he didn't put it in an answer.
    – calocedrus
    Jul 22 at 1:06
  • 1
    @calocedrus "....a breeze" I just got that ;)
    – DjinTonic
    Jul 22 at 10:53

Airtightness fits perfectly [per calocedrus comment I retract this word] I believe since, as has been pointed out, odors travel through air.

Presumably, airtightness comes from the word airtight, adj, which Merriam- Webster defines as:

impermeable to air or nearly so, e.g. an airtight seal

I found this references on a company website describing one of their attic insulation services:

Airtightness is primarily focusing on the elimination of all unintended gaps and cracks on the external envelope of the building. [Building systems company website]

  • 1
    Odors are not air. Polyethylene film can create an airtight barrier, but some molecules (like carbon dioxide) can pass through. (Which is why polyethylene terephthalate is used for carbonated beverages).
    – Theodore
    Jul 21 at 16:25
  • 1
    Good idea, but airtightness doesn't pertain only to odors. If I say "this room is airtight" one will not get it that I'm referring to odors being able to come in or out, though it could be implied.
    – calocedrus
    Jul 23 at 2:47
  • odor insulation (simple and straightforward, read my analysis below and the conclusion)
  • odor-blocking insulation could also be a close equivalent to thermal insulation but blocking and insulation seems redundant, one doesn't say heat-blocking insulation.
  • odor-proof/-ing (first proposed by Andrew Leach in one of the first comments, proposed as odor-proofing in DjinTonic's answer above (+1 for this))
  • odor-tight (my reply to Andrew's comment)

The topic raised interesting comments, some of which pertaining to science (unexpected, but a pleasant surprise). So here is some further analysis, please do comment as I'm sure the topic can raise more discussion.


An odor is the result of the interaction between molecules having certain properties and olfactive sensors, and their subsequent analysis/processing. Note that these molecules may be detected in other ways such as with a chromatograph, spectrograph, etc but with such instruments they will not produce an odor.

Odors do not travel by conduction nor radiation, but by convection (the air is the carrier), they are not a form of energy. They ultimately travel by air (though other gazes may work and odor can pass through thin solids - membranes, plastic films, porous materials...)

Thermal, heat

Thermal pertains to heat. Heat, as sound, results from the vibration/interaction between molecules and/or atoms, it is not dependent on the chemical nature of the molecules themselves (nitrogen N2 has no odor but can transport heat or heat be created from it; at the same time, quantitatively speaking, some molecules or atoms may contribute to produce different amounts of heat depending on their nature). Heat is a form of energy and may be used to produce work. It can be transferred by convection, radiation or conduction. Heat can be quantified.


Sound is a vibration, carried by a gaz, a solid or a liquid, and as for odor, has be received by a sensor and be further processed/analyzed to be interpreted as a sound (but note that sounds may exist even if not received by a sensor or be processed or analyzed, there are sounds one may not perceive or be aware off, yet they can exist). Sound can't be quantified by itself (though one says loud or soft sound, these are not quantities) unless a physical quality is added: e.g. sound pressure. In sound pressure, sound is a noun used as an adjective.

Conclusion: despite differences (semantically, grammatically, physically, and from a chemical point of view), heat (thermal), sound and odor all share the fact that they can be isolated from a receiver. Hence odor insulation seems to be a logical equivalent (semantically speaking) to thermal and sound insulation, but still not the grammatically speaking equivalent to thermal insulation: from that perspective it is closer to sound insulation.

  • To TheDownvoter(s): Please help me to improve by commenting on why you downvoted my answer; as I wrote, "please do comment'. So please be constructive. No hard feeling for a downvoting, so don't fear any retaliation!
    – calocedrus
    Jul 24 at 5:08

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